Well sounding gun



y 1951' B. H. TOWELL ETAL 2,993,554

WELL SOUNDING GUN 2 Sheets-Sheet 1 Filed May 31, 1956 Air July 25, 1961Filed May 31, 1956 B. H. TOWELL EIAL WELL SOUNDING GUN 2 Sheets-Sheet 2United Stat s Patent 2,993,554 WELL SOUNDING GUN Billy H. Towell,Bellaire, and Robert B. Heath, Houston, Tex., assignors to Texaco Inc.,a corporation of Delaware Filed May 31, 1956, Ser. No. 588,533 3 Claims.(Cl. 181-.5)

This invention relates to a cartridge firing device for use withacoustic well sounding equipment employed for acoustically determiningthe depth from the surface to the fluid level in the well.

Well sounders of the present type generally comprise an assembly whichincludes pressure-proof pipes, fittings, and instruments which aremechanically connected to the well in the test. Such instrumentsessentially include a cartridge firing device, microphone, recorder,wadding catcher and bleeding valve.

Typical well sounders record directly on chart paper sound pulsesproduced upon the firing of a blank cartridge in the annular spacebetween the tubing and casing of a well. Sound pulses are reflected bytubing collars, tubing catchers, and any other constriction orenlargement of the gas column above the fluid. The depth to the fluidcan be determined by multiplying the number of tubing joints by theaverage tubing length.- The distance to the fluid is often manythousands of feet and the sound pulses generated by the cartridge in thefiring device or gun must be suflicient to travel the distance to thefluid and back to the microphone without nullifying attenuation.

The problem of firing a cartridge into a producing well to create soundtherein is somewhat unique because pressures as high as 15-00 lbs. ormore per square inch are frequently encountered and the moving parts ofthe firing device must be sealed against such pressures and againstcontamination by corrosive well gases, oily fumes and powder fumes whichare forced into it by said pressure. The firing device or gun must bedesigned to cope with this unique problem and such a device should alsoinclude adequate safety means to protect the equipment from prematurefiring of the cartridge.

Accordingly, an object of the present invention is to provide animproved firing device in which blank cartridges can be exploded into awell and which is sealed to prevent contamination by corrosive wellgases and powder fumes from the exploded cart-ridge. Another object ofthe invention is to provide a firing device embodying safety featureswhich prevent the premature firing of the cartridge as when the deviceis being prepared prior to firing. A still further object of theinvention is to provide a firing device having a barrel designed toobtain a much greater efliciency from the cartridge which is fired.Another object of the invention is to provide an improved well-soundinggun which is safer, easier to load, and easier to fire.

In order to accomplish the foregoing and other objects in accordancewith this invention, there is provided a cartridge firing device for usewith acoustic well-sounding equipment comprising a barrel having a chokein the exit end thereof whereby greater efficiency from the explodedcartridge is obtained, means to detonate said cartridge, and means toconnect said firing device to said well sounding equipment. It has beenrealized that chokes in shot gun barrels to concentrate the pellets fromfired shot gun shells are well known. However, a novel effect isobtained by using a choke in the barrel of a firing mechanism forwell-sounding to modify the shape of the sound pulse to obtain a lowerfrequency. This is extremely advantageous since a 'low frequency pulsewill travel much further than a relatively high frequency pulse. Themeans for detonating the cartridge comprise a breech block coupled tothe barrel, a firing pin mounted in the coupled end of the breech blockand in axial alignment with the barrel, a spring loaded hammer mountedin the breech block, said hammer biased toward said firing pin and inaxial alignment therewith, said hammer having a cocking catch and asafety catch along its length, and a spring biased sear pin mounted inthe breech block and urged toward the hammer whereby it is engageablewith the cocking catch and the safety catch, the safety catch beingpositioned at a lesser distance from the cocking catch than the distancebetween the fining pin and the hammer when the sear pin is engaged inthe cocking catch whereby the sear pin will engage the safety catch whenthe hammer rebounds after hitting the firing pin.

Packing means in the form of 0 rings are associated with said firing pinto prevent the entrance of corrosive gases into the breech block.

The invention also includes the method of determining the depth from thesurface to the fluid level in a well comprising creating low frequencysound pulses by firing a cartridge into a well from a firing devicehaving a choked barrel, converting reflected sound pulses to electricalpulses, and recording said electrical pulses.

The invention will be further understood by reference to theaccompanying drawing wherein FIG. 1 represents a side sectional view ofthe firing device and FIG. 2 is a view showing the well soundingequipment connected to a well.

The device is connected to the remainder of the wellsounding equipmentrepresented by pipe 2 by means of an internally threaded barrel housing4, the threaded connection being of 'sufficient strength to withstandthe high pressure of the well. The barrel 6 is coupled to the breechblock 8 by means of internally threaded union nut 10 which engages theexternal threads on barrel housing 4. Nut 10 has an internal flangedportion 12 which is adapted to fit over the breech block 8 and engagethe extending flanged portion 14 at the coupling end thereof. Within aninternally threaded cavity 15 at the coupling end of breech block 8,firing pin guide 16 is threadedly secured. The firing pin 17 withfiring-pin head 18 is reciprocably mounted in the firing pin guide 16and firingpin head 18 is normally urged into a stop position with theshoulder of the chamber opening 19 in the breech block 8. Coil spring 22which surrounds the firing pin causes this biased engagement offiring-pin head 18 with the shoulder of the chamber opening 19. O-rings23 and 24 are provided around the firing pin and firing-pin guide,respectively, to prevent the escape of the high pressure well gases andalso to prevent corrosive powder fumes and corrosive well gases fromentering the firing mechanism. O-ring 23 is held in position by O-ringretainer 26 which, in turn, is fastened to the firing pin guide 16 bymeans of screws or the like at 28.

Within the breech block 8 a reciprocably mounted hammer 20 is normallyurged toward the firing pin by spring 32. The spring 32 is confinedbetween the flange 34 protruding laterally from the hammer 20, at oneend, and a spring retainer 36 fastened to the breech block 8 by screwmeans 37 or the like at its other end. The hammer 20 is provided with ahandle 30 to facilitate cocking.

Extending perpendicularly from and through the breech block 8 is searpin 38 which is urged into engagement with the side of hammer 20 bymeans of coil spring 40 which is confined between a flanged portion 41on the sear pin and sear pin retainer 42. The scar pin 38 is usuallyprovided with a ring through hole 44 to facilitate firing. Hammer 20 hasa cocking slot or catch 46 which is seen engaged with end 48 of the searpin 38. A safety catch or slot 50 is provided in hammer 20 at a lesserdistance from the cooking catch 46 than the distance between "firing pin17 and hammer 20 when sear pin 38-is in engagement with cocking catch"46. A channel portion 52 is provided in the hammer 20 between catch 46and extending slightly past catch 50 to maintain the sear pin in thecorrect position on the hammer relative to the catches 46 and 50. Thehammer 20 when released from the cocked position will travel fast enough[to prevent the sear pin 38 from engaging safety cateh 50. However,after hammer 20 strikes firing pin 17, it will rebound slightly and thesear pin 38 will engage safetycatch 50 at this point. This holds thehammer 20 safely away from the head 18 of firing pin -17, therebypreventing the accidental detonation of a new cartridge.

Cooking is accomplished by pulling sear pin 38 out of safety position 50and then pulling hammer 20 out until sear pin 38 engages in cocking slotor catch 46.

Barrel 6 is provided with a choke or restricted portion at 54. Thiscombination of barrel and choke permits a surprisingly greater eificientutilization of the energy from the cartridge 68 to be used by modifyingthe sound pulse to a lower frequency when the cartridge is fired. 'Thisallows the use 'of a cartridge containing less powder and consequentlyreduces the expense and ultimate corrosion caused by excessive smokefrom a cartridge or shell burning more powder. In the preferredembodiment, the firing device is designed to accommodate a .410 gaugeshotgun shell and the barrel length is about 12 inches long. The chokeis of an inch and extends over the last A inch of the exit end of thebarrel.

As seen in FIG. 2, the well sounding equipment is attached to the wellat valve 60 by means of a bushing and union. A wadding catcher 62 isplaced in a section of pipe below the exit end of barrel 6 to preventthe wadding from the cartridge entering into the well. Bleeder valve 64is provided to permit release of pressure in the well sounding equipmentafter valve 60 is closed so that the firing device can be removed.

Microphone 66 converts the sound pulses to electrical impulses andtransmits them to the recorder.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof and, therefore, only such limitations should beimposed as are indicated in the appended claims.

We claim:

1. A cartridge firing device for use with acoustic well soundingequipment comprising a barrel, a breech block coupled to said barrel, afiring pin mounted in the coupled end of the breech block and in axialalignment with 'said "barrel, a 'spring'loaded hammer mounted'in thebreech block, said hammer biased toward said firing pin and in axialalignment therewith, said hammer having a cooking catch and a safetycatch along its length, a spring biased sear pin mounted in said breechblock and urged toward said hammer whereby it is rengageable with saidcocking catch and said :safety'catch, said safety catch being positionedat a lesser-distance from the cooking catch than the distance betweensaid firing pin and said hammer when said sear pin is engaged in saidcocking catch whereby the sear pin will engage the safety catch whensaid hammer rebounds after'striking said firing pin, and means toconnect said firing device to said well sounding equipment.

2. A cartridge firing device as described in claim 1 wherein said hammerhas a channeled portion along its length between said cocking catch andsaid safety catch and extending slightly past said safety catch wherebythe end of said sear pin will ride in said channel when the device isfired.

3. A cartridge firing device for use with acousticwell soundingequipment comprising a barrel, a breech block coupled to said barrel, afiring pin mounted in thecoupled end of the breech block and in axialalignment with said barrel, packing means associated with said firingpin to prevent the entry of corrosive gases into said breech block, aspring loaded hammer mounted in the breech block, said hammer biasedtoward said firing pin and in axial alignment therewith, said hammerhaving a cocking catch and a safety catch along its length, a springbiased sear pin mounted in said breech block and urged toward saidhammer whereby it is engageable with said cocking catch and said safetycatch,

said safety catch being positioned at a lesser distance from the cockingcatch than the distance between said firing pin and said hammer whensaid searjpin is engaged in said cocking catch whereby the sear pin willengage the safety catch when said hammer rebounds after striking saidfiring pin, and means to connect said firing device to said wellsounding equipment.

References Cited in the file of this patent UNITED STATES PATENTS570,458 Coston Nov. 3, 1896 602,422 Batcheller Apr. .-19, .18981,422,865 Jobson July 18, 1922 1,772,656 Abbott Aug. 12, 1930 2,232,476Ritzmann Feb. '18, 1941 2,560,911 Wolf July 17, v'1

